Cloud Run Functions data model

[inlined]

Thanks for your patience. I've got part one of 2-3 on getting some PoCs ready for CRF. This just extends the data model to support the RunV2 API (needed for the submit build stuff), the service<->endpoint stuff, and the changes that popped up with assertExhaustive once a new type has been added.

This PR exposed two bugs (not fixed):

1. The Eventarc source is not converting function IDs to service IDs (which can use a utility function where there is a TODO in the runv2 code)
2. The billing calculator was created when GCFv2 had a different SKU and that's no longer the case. But the billing change will also go out, so we need to figure out which way to fix it.